Candidate: The candidate is committed to a career in academic dentistry, with a focus on patient-oriented research. This award will enable the candidate to achieve his immediate career objective, which is to gain additional training and experience in patient-oriented research. This will in turn enable him to achieve his long-term career goal, which is to become an independent funded investigator in patient-oriented research. Mentors: The primary mentor will be Dr. Douglas Peterson who has extensive expertise and experience in patient-oriented research related to oral mucositis. The co-mentor will be Dr. Carol Pilbeam who conducts NIH-funded basic science research related to the cyclooxygenase (COX) pathway. This complementary combination of clinical and basic science expertise will ensure a comprehensive training program. Environment: A well-established research program in the proposed research area is in place. An NIH-funded GCRC provides a comprehensive range of supportive services for clinical research. Strong evidence of institutional commitment to the candidate's career development is documented in the application. Career Development Plan: The didactic component will include a range of course-work in areas relevant to patient-oriented research. The clinical component will include experience in at least three separate clinical research studies. The laboratory component will include hands-on experience in RT-PCR and ELISA. Research Plan: Most patients treated with radiation therapy for head & neck cancer develop ulcerative oral lesions called oral mucositis (OM). OM is painful and compromises nutrition & quality of life. OM causes interruptions in radiation therapy, thus adversely affecting cancer therapy outcomes. Hypothesis: COX-2 contributes to mucosal injury in radiation-induced OM. Specific Aims: 1. To determine effects of a selective COX-2 inhibitor on clinical mucosal injury in radiation-induced OM. 2. To examine mechanisms leading to mucosal injury in radiation-induced OM and effects of the selective COX-2 inhibitor on these mechanisms.